Barium Hyponitrite, BaN2O2

Barium Hyponitrite, BaN2O2, may be obtained as a crystalline precipitate by the action of sodium hyponitrite on barium chloride solution, or of the silver salt on an ammoniacal solution of barium acetate and subsequent washing of the precipitate with ammonia, alcohol, and ether, followed by rapid drying in air. Large needles are obtained when very dilute solutions are used. It is also produced by the action of nitric oxide on barium ammonium.

It is obtained both as the anhydrous salt and as the tetrahydrate, BaN2O2.4H2O. The tetrahydrate readily effloresces. Barium hyponitrite is only slightly soluble in water, the solution giving an alkaline reaction. It is decomposed by dilute acids with the evolution of nitrous acid.

An acid salt, BaH2(N2O2)2, crystallising in long needles and readily soluble in water, may also be prepared, but not in a pure condition.

By crystallising the neutral salt from acetic acid solution a compound, BaN2O2.Ba(CH3COO)2.2CH3COOH.3H2O, is obtained. It is less stable than the corresponding calcium and strontium compounds.